Hello all,
Well after the issue I had with my truck a while back after an accedent everythings been working great. But just the other day I was out running about getting a few things done.

So everything was going good and when I looked at my guage's the Temp guage was at about 220-230 I had the A/C on so I turned it off and it went down a little bit. So I pulled over got a bite to eat and took off again.

Now it ran around the 200 mark but did climb to 220+ especially when in town. It has always ran below the 200 mark I would say 180-190.

I replaced the T-stat with a new one but still the same results staying around 200+. I tried to bleed out the system a bit more and all seem's good. Water seem's to be flowing good.

Has a new radiator, water pump, T-stat...

I had it running today and used a hand held temp guage to temp at the T-stat and from what I could tell it was about 185 or so.

Think maybe the temp sensor or temp sending unit might be going bad or gone bad?

Any idea's would be appreciated.

Thanks, George

 

Check the fan clutch.

 

Thanks Zman. I was starting to think the same thing after I wrote this post.

Went down and grabbed a new one so I'll back to work.

 

check the coolant temp sensor. i would have to say if the fan was going you would hear it slipping. it makes that simmiler sound as first starting off before the fan clutch fully ingages. but most times the fan clutch just freezes and runs engine speed all the time.

 

You said you got a new radiator. Which brand did you get, and does it have the same flow and number of fins as the original?

 

New fan clutch didn't do it. Still about 200+. I thought it might have been that since it had very little resistance when turning by hand.

Thinking the sensor next. I used a temp gun and got it as close to the T-stat as I could and got a reading of 185 so I'm thinking maybe the sensor is bad and giving false readings to the guage.

Radiator was bought new from a radiator shop. Haven't had an issue since July when I installed it.

Not leaking any coolant

 

If the gauge is off consistently, just live with it. Not like they were incredibly accurate to begin with. So long as the PCM gets a good idea of what engine temp is, and you know your gauge reads a little high, its all good.

Besides, given the stock equipment, it is unlikely that a new sensor will make any difference.....

 

the sensor is like 10 bucks at advanced auto it takes all of 5 minutes to install and as for Hey YOU's idea of the pcm getting a good idea that wrong. you will lean the motor out ever so slightly which yes is great for power but bad for everything else. also if its acting up now who knows what it will do. mine was reading low until i replaced mine. great for power but the gas pump loved me. and my check book hated it

 

What year is your truck?

 

Oh sorry... Its a 1994 1500 4x4 with a 5.9.

I'll run down and pick up a temp sensor today and try that. Hopefully thats the issue.